The present invention relates to a padlock with lockable shackle in accordance with the preamble of claim 1.
A plurality of such padlocks exist, because they are also known as padlocks (English). In particular, with such padlocks, wherein, once the shackle is locked, the padlock can no longer be opened without destroying it, there is the problem, on the one hand, of preventing as much as possible attempts to tamper with the lock and, on the other hand, of rendering said tampering visible and detectable.
Thus, for example, the U.S. Pat. No. 4,779,911 discloses such a padlock, which is constructed of few parts. Once the shackle has been locked, it cannot be opened without breaking it. In this respect the two ends of a U-shaped shackle, made of metal, are disposed in a box-shaped housing. In the unused, open state only one end of the shackle can be slid longitudinally between two stops and swung sideways in this housing. Thus, the shackle can be used as prescribed, for example, by inserting the free end into one eye or several eyes. Finally the free end can be inserted into the corresponding opening in the padlock housing, where there are springy retaining means, which are inaccessible from the outside and which at this stage hold these ends of the U-shaped shackle immoveably. Thus, the springy retaining means engage with an annular groove, designed on the end of the shackle. Now the padlock must be opened by serving the U-shaped shackle with a tool, thus rendering the padlock useless for reuse.
This prior art embodiment of a padlock is, indeed, simply constructed from only a few parts, but is exhibits some shortcomings, especially with respect to protection against tampering.
The object of the present invention comprised at this stage of providing such a padlock, which is believed to be even simpler in its construction and at the same time is believed to provide better protection against tampering.
The invention solves this problem with a padlock with the features disclosed in claim 1.
One advantage of such an inventive padlock is that it can be manufactured preferably in one piece and is very well protected against tampering owing to the fact that the locking members are not accessible from the outside and are not open in the interior of the housing. Since the padlock is manufactured in one piece, it still exhibits, despite its protection against tampering, the advantages of a simple construction. As an inexpensive mass produced article, such a padlock is especially suitable for application in areas requiring good protection or good protection against tampering.
Preferred designs of the invention follow from the dependent claims 2 to 9.
One embodiment of the present invention is explained in detail below with reference to the drawings.